Such devices are installed in the clarified effluent flow from a sewage treatment plant. This effluent flow is conveyed through an open canal into which the UV disinfecting devices of this type are inserted. Elongated UV emitters, in the form of gas-discharge lamps, are disposed essentially horizontally and with their longitudinal axes in the flow direction. Depending on the effluent quantity, a greater or smaller number of emitters is disposed parallel, next to one another, and one above the other, so that there is no point in the effluent flow which is more than a predetermined maximum distance from the radiation sources. In this manner, the bacteria present in the clarified effluent are reliably killed and the effluent is thus disinfected.
A UV disinfecting device of this type is known from EP 0 080 780 and corresponding U.S. Pat. No. 4,482,809. In this structure, a number of UV lamps are surrounded by cylindrical casing sleeves and, together with them, constitute lamp units. A number of lamp units are disposed horizontally, parallel to one another, and one above the other, wherein the casing sleeves are each disposed in a water-tight fashion in bases that are fixed to the frame. The inside of the casing sleeves, the inside of the bases, and the inside of the frame thus communicate with each other, so that the electric supply lines can be routed through these hollow spaces.
In this structure, it is problematical that on the one hand, this system is technically expensive. On the other hand, in order to replace a single UV lamp that has become defective, the system that is closed in a water-tight fashion has to be opened, which in particular can lead to sealing problems later, particularly when there is external contamination. Finally, there is the not-insignificant danger that with a single leak in the entire system, all of the hollow spaces that communicate with each other become flooded with effluent and, as a result, an entire vertical row of UV emitters fails and is severely damaged.